[coreboot - Project ideas #451] Fix POST code handling

[Alexander Goncharov]

Issue #451 has been updated by Alexander Goncharov.

File Fix_POST_code_handling_GSoC_Joursoir.pdf added

Just in case, I attach my unselected GSoC project proposal on this topic

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Project ideas #451: Fix POST code handling
https://ticket.coreboot.org/issues/451#change-1514

* Author: Felix Singer
* Status: New
* Priority: Normal
* Target version: none
* Start date: 2023-01-29
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coreboot supports writing POST codes to I/O port 80. There are various Kconfigs that deal with POST codes, which don’t have effect on most platforms. The code to send POST codes is scattered in C and Assembly, some use functions, some use macros and others simply use the `outb` instruction. The POST codes are duplicated between stages and aren’t documented properly.

## Tasks

* Guard Kconfigs with a depends on to only show on supported platforms
* Remove duplicated Kconfigs
* Replace `outb(0x80, ...)` with calls to `post_code(...)`
* Update Documentation/POSTCODES
* Use defines from console/post_codes.h where possible
* Drop duplicated POST codes
* Make use of all possible 255 values

## Requirements

* Knowledge in the coreboot build system and the concept of stages
* Other knowledge: Little experience with C and x86 Assembly
* Hardware requirements: Nothing special

## Mentors

* Patrick Rudolph [e-mail]
* Christian Walter [e-mail]

---Files--------------------------------
Fix_POST_code_handling_GSoC_Joursoir.pdf (102 KB)